Dump it down the toilet or sink. Unless you're talking large amounts, then I'm sure there is a hazardous waste disposal site nearby. But regular drain and fill, couple gallons maybe? Down the toilet. Just don't dump it in the sewer.
are you serious??
Take it to your local autoparts. around here pepboys, advance, and napa will all take antifreeze and oil. DO NOT dispose of it in the sink/toilet.